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Bituminous Stabilized Materials Guideline: Inception Study. Project Funded By: Gautrans Sabita. Background. ETB Materials ; Two guidelines exist: Sabita Manual 14 (1993) Sabita Manual 21 (1999) Foamed Bitumen Materials: TG2 Interim Guideline.
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Bituminous Stabilized Materials Guideline:Inception Study Project Funded By: Gautrans Sabita
Background • ETB Materials; Two guidelines exist: • Sabita Manual 14 (1993) • Sabita Manual 21 (1999) • Foamed Bitumen Materials: • TG2 Interim Guideline • Guidelines widely used, but there is a need to: • Modernize • Improve • Create a single, combined guideline
Main Deficiencies: Mix Design • Lack of a suitable Curing Method • More appropriate tests to assess: • Flexibility • Shear Strength • Durability
Main Deficiencies: Structural Design • Conservative structural designs (catalogue and design charts) • Questions about 2-Phase modelling • Need to incorporate curing effects • Limited database used for development • Lack of validation using long term field data
Phase 1: Inception Study Mix Design (K Jenkins) Structural Design (F Long) Phase 2: Mix Selection Criteria Phase 3: Mix Design Issues Refinement and Guideline Compilation Phase 4: Structural Design Issues Phase 5: Construction Issues Phase 5: Guideline Finalization Project Structure
Inception Study Objectives:Mix Design • Identify Durability Test and gather curing data • Investigate Triaxial Testing protocols • Investigate Strain-at-Break • Plan and re-direct further activities
Inception Study Objectives:Structural Design • Gather available performance data (LTPP & HVS) • Analyze and identify trends (if any!) • Assess key deficiencies in available information • Plan and re-direct further activities
Progress to Date: Structural Design • 126 Roads appeared on radar • 104 Emulsion Treated Base • 22 Foamed Bitumen • Only some roads suitable to study • Duplication amongst reported projects • Many roads recently constructed • Some very low traffic and/or no data • Urban legend
Some Best Candidate Projects • HVS Tests: • N3-4, Mooi River • N2-16, East London • P9-3 Petrus Steyn • P243-1 Vereeniging • N7, near CT • N12-19 (current) • N12-19 (1974) • N2-16 (1982) • N3-4 (1988) • N4-5X (1997) • N4-1 (1997) • MR27 (1988) • N1-1 (1984) • N1-13 & 14 (1980) • P504 (1995) • Same-Himo Project (1992, LTPP study) • N7-7 (1987) • P24-1 (1999) • ± 20 Promising projects in total
Classification Approach For each project, assess and classify: • ETB/Foam source material • ETB/Foam stability & flexibility properties • Support Layer quality and class • Subgrade quality and class • Maximum deflection range before/after construction • Standard axle range accommodated in field or HVS Vision: • Develop a design approach that relies on measurable, non-ambiguous parameters • Ensure transparent, straightforward validation of recommended designs